Electrical sound-converting apparatus



" Y 4 ELECTRICAL: SOUND CONVETNG' APPATUS fined Img. 2; 1922 4L Afm@ im? ne Hi." lileteieteel een l eppumioe im. August e, ieee. eeriai rre. meets.

To all whom, t may conceive:

Be it known tliet l, CHARLES Vif'. .PermesoN, e citizen of tbe United States, residing et Seattle. in the county of King and State of lVasliington, have invented certain new and useful improvements in Electrica-l Sound-Converting Apparatus; and l do hereby declare tbe following to be e full7 clear, :wely description of the invention, such :is will enable others'sliillecl in the irrt to wliiieb it eppertains to understand tlie same.

My invention relates to irriprovements in the electro-magnetic operating system of the general class` of apparatus, known'es telephone receivers,"'7 and more especially of the class linewri es L loud speakers. lt mey also be used es e telephone transmitter.

The objects of my invention sire to pro-r vide an electromagnetic operating system for sound reproducing or converting epperatue, in which tbe eiioieney in converting electrical puleetions int-o ineeiienieel vibretion and sommi waves, and conversely of converting sound Waves and mechanical vibrations into alternating" electric Currents, is unusually high, to provide such e. device in which. there ere no rmmible coils or {leziibleg connections to get out of orxier; and to provide a magnetic system which takes a very smell ernennt of field current.,

My invention may be clearly uiiierstoocl by reference to the accompanying sehe-metio drawing in wliieh -l represente en iron core, preferably lemineted, with pole pierces 2 end 2', 3 is ai flexible iron ermetiire held in place iii the yol'ire et its outer einde el end 4 and the pole pieces et ite center by smell air gaps 5 emi. 5", ero-imei the pole pieces lielr coils 6 emi 6, emi-` 7 around the armature but not touching; it ere the operating coils, 8 is e ieplriregm, 9 is o link eennecting diaphragm 8 to ermeture 3, and 10 is whole time pole piece 2 iter link 9 to pese-tint.

The operetion of the device is as follows: The field wiresere connected to e Suitable source of direct curreritend the pole tips 2 end-2 become very strongly .niegnet ized N end S es shown in the drawing. Nowwhen the alternating operating rent ie oonneeteel to the fermeture wiree.-

tbe center ef 3 be eines 4ietirfiefl f i-iteruetely Il enrl S once reif' ec /ii etternetion ef Julie operating current. Wittem Lhence the device een be used the center of tile armature is N the ermature is strongly repelled from the strong N fieldpole mid at the seme time is strongly attracted by the strong results in the armature springing downward nearer pole 2 than. pole 2, and this downward motion is transmitted thru link 9 to diaphragm 3 and then to the air. Similerly when the @enter .of the armature is E, diaphragm 8 is pushed upwardly, which causes e eempressiori half of'a sound weve to be formed. (lonveleely, when sound wev strike diaphragm 8 armature 3 is made to vibrate which @euses en alternating' tiux to flow tliru the amature iron inside of armature eoile Z enel 7 sind this induces en E. il@ in eecorclenee wit. vtim sound wevee, end

ee e tramsinitter.

The greet efli-cieney of the device es e loud speaker .co-mee from the teef; that there is such e (iirect interaction between tile strong field uzr 11ml the elf-mature fluff right at the point of the :armature Where the force is transmitted to the diaphragm, from there being paths ofi such low reluctance for both the field linx end fermeture iiux es is possible by this desigm, and from the feet that the whole core may be laminated, thereby doing ewey with lnost of' the eddy eur-rent losses. The iield flux density is kep-t relatively low so that tile eore 05ers e, geod permeable return path for the eriifieturev flux. .The eir gepfl, 5 end 5 :ire merle short also to keep reluctance low, but ello-W Si field pole, and this` @m tlieermeture coils4 plenty of fer vibration of armature 3. No ielcl ller lo'vfs @the eimetsire end this leaves the armate e in e very permefibie condition toi' 'the alternating ermeture flu-iz.

llt might be tiieuglit that one or" the vfield esile could be elimineted :incl twice the number oi' empere turns put on the remaining coil without inpziiring tbc operetion of the devicebut this: ie not the case since the' one field coil woulel eet es e short cirouted secondary coil to the 'eiterneting ermeture finir, When two field coils of equal numbere ot terne are ueetl tir' es im the drewiriej, tbe volta riuee coil is in tbe ege-ponte nii f' tien t by eeme en seriess ne inem ting currentllewe in tbe field Jure the2 eiiclthat u 

